1. Field of the Invention
The present application relates to phase change memory technology, and more particularly to phase change memory suitable for high density implementations.
2. Description of Related Art
PCM is a promising memory technology. PCM stores data by establishing higher resistance amorphous, and lower resistance crystalline phases in an active region of the cell, which result in a programmable level of resistance that represents data. PCM however can suffer a problem of structural relaxation of the crystalline phase material and recrystallization of the amorphous phase material over time in PCM which limits data retention. To increase data retention, the programming technique can require wide margins for safer long term storage. However, this comes at the cost of slower write procedures. Slow write can limit the usefulness of PCM memory in some high speed applications.
Thus, it is desirable to provide a technology that can expand the types of applications for PCM memory.